文章目录
-
- 一、搭建父工程
-
- 1.1 选择菜单file-new project ,弹出窗口中左侧菜单选择Maven ,点击next按钮
- 1.2 填写GroupId和ArtifacetId ,点击next按钮
- 1.3 点击Finish 完成
- 1.4 删除src文件夹
- 1.5 修改pom.xml 添加以下配置
- 1.6 当IDEA右下角弹出提示 ,点击Enable Auto-Import 自动导入依赖
- 二、搭建公共子模块tensquare_common
-
- 2.1 右键点击工程,弹出菜单选择New-Module 弹出窗口选择Maven ,点击next按钮
- 2.2 点击finish
- 2.3 创建返回结果实体类
-
- 2.3.1 新建entity包,包下创建类Result
- 2.4 创建类PageResult
- 2.5 创建返回码定义类
- 2.6 分布式ID生成器
- 三、小结
一、搭建父工程
1.1 选择菜单file-new project ,弹出窗口中左侧菜单选择Maven ,点击next按钮
![](https://img.laitimes.com/img/__Qf2AjLwojIjJCLyojI0JCLiAzNfRHLGZkRGZkRfJ3bs92YsYTMfVmepNHL9cmaOh3ZU5keBRVT3V1MMBjVtJWd0ckW65UbM5WOHJWa5kHT20ESjBjUIF2X0hXZ0xCMx81dvRWYoNHLrdEZwZ1Rh5WNXp1bwNjW1ZUba9VZwlHdssmch1mclRXY39CXldWYtlWPzNXZj9mcw1ycz9WL49zZuBnLzYTMyAjNwAjM1IjNwkTMwIzLc52YucWbp5GZzNmLn9Gbi1yZtl2Lc9CX6MHc0RHaiojIsJye.png)
1.2 填写GroupId和ArtifacetId ,点击next按钮
1.3 点击Finish 完成
1.4 删除src文件夹
1.5 修改pom.xml 添加以下配置
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.tensquare</groupId>
<artifactId>tensquare_parent</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<name>tensquare_parent</name>
<description>十次方项目-小洋人最happy</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.1.RELEASE</version>
<relativePath/>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
</project>
1.6 当IDEA右下角弹出提示 ,点击Enable Auto-Import 自动导入依赖
至此,父工程搭建完成。
二、搭建公共子模块tensquare_common
2.1 右键点击工程,弹出菜单选择New-Module 弹出窗口选择Maven ,点击next按钮
2.2 点击finish
2.3 创建返回结果实体类
2.3.1 新建entity包,包下创建类Result
该类用于控制器类返回结果。
代码如下:
package entity;
/**
* Created by me on 2019/6/25.
*/
public class Result<T> {
private boolean flag;
private Integer code;
private String message;
private Object data;
public Result(boolean flag, Integer code, String message, Object data) {
this.flag = flag;
this.code = code;
this.message = message;
this.data = data;
}
public Result(boolean flag, Integer code, String message) {
this.flag = flag;
this.code = code;
this.message = message;
}
public Result() {
}
public boolean isFlag() {
return flag;
}
public void setFlag(boolean flag) {
this.flag = flag;
}
public Integer getCode() {
return code;
}
public void setCode(Integer code) {
this.code = code;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
}
2.4 创建类PageResult
该类用于返回分页结果。
代码如下:
package entity;
import java.util.List;
/**
* Created by me on 2019/6/25.
*/
public class PageResult<T> {
private long total;
private List<T> rows;
public PageResult(long total, List<T> rows) {
this.total = total;
this.rows = rows;
}
public long getTotal() {
return total;
}
public void setTotal(long total) {
this.total = total;
}
public List<T> getRows() {
return rows;
}
public void setRows(List<T> rows) {
this.rows = rows;
}
}
2.5 创建返回码定义类
将错误码统一归类管理。
代码如下:
package entity;
/**
* Created by me on 2019/6/25.
*/
public class StatusCode {
public static final int OK = 20000;// 成功
public static final int ERROR = 20001;// 失败
public static final int LOGIN_ERROR = 20002;// 用户名或密码错误
public static final int ACCESS_ERROR = 20003;// 权限不在不
public static final int REMOTE_ERROR = 20004;// 远程调用失败
public static final int REP_ERROR = 20005;// 重复操作
}
2.6 分布式ID生成器
由于我们的数据库在生产环境中要分片部署(MyCat),所以我们不能使用数据库本身的自增功能来产生主键值,只能由程序来生成唯一的主键值。
我们采用的是开源的 twitter的 snowflake (雪花)算法。
默认情况下41bit的时间戳可以支持该算法使用到2082年,10bit的工作机器id可以 支持1024台机器,序列号支持1毫秒产生4096个自增序列id .
SnowFlake的优点是,整体上按照时间自增排序,并且整个分布式系统内不会产生ID碰撞(由数据中心ID和机器ID 作区分),并且效率较高。
经测试,SnowFlake每秒能够产生26万ID左右
在
tensquare_common
工程中创建
util
包,新建
IdWorker.java
文件(分布式ID生成器),将如下代码拷入即可。
package util;
import java.lang.management.ManagementFactory;
import java.net.InetAddress;
import java.net.NetworkInterface;
/**
* <p>名称:IdWorker.java</p>
* <p>描述:分布式自增长ID</p>
* <pre>
* Twitter的 Snowflake JAVA实现方案
* </pre>
* 核心代码为其IdWorker这个类实现,其原理结构如下,我分别用一个0表示一位,用—分割开部分的作用:
* 1||0---0000000000 0000000000 0000000000 0000000000 0 --- 00000 ---00000 ---000000000000
* 在上面的字符串中,第一位为未使用(实际上也可作为long的符号位),接下来的41位为毫秒级时间,
* 然后5位datacenter标识位,5位机器ID(并不算标识符,实际是为线程标识),
* 然后12位该毫秒内的当前毫秒内的计数,加起来刚好64位,为一个Long型。
* 这样的好处是,整体上按照时间自增排序,并且整个分布式系统内不会产生ID碰撞(由datacenter和机器ID作区分),
* 并且效率较高,经测试,snowflake每秒能够产生26万ID左右,完全满足需要。
* <p>
* 64位ID (42(毫秒)+5(机器ID)+5(业务编码)+12(重复累加))
*
* @author Polim
*/
public class IdWorker {
// 时间起始标记点,作为基准,一般取系统的最近时间(一旦确定不能变动)
private final static long twepoch = 1288834974657L;
// 机器标识位数
private final static long workerIdBits = 5L;
// 数据中心标识位数
private final static long datacenterIdBits = 5L;
// 机器ID最大值
private final static long maxWorkerId = -1L ^ (-1L << workerIdBits);
// 数据中心ID最大值
private final static long maxDatacenterId = -1L ^ (-1L << datacenterIdBits);
// 毫秒内自增位
private final static long sequenceBits = 12L;
// 机器ID偏左移12位
private final static long workerIdShift = sequenceBits;
// 数据中心ID左移17位
private final static long datacenterIdShift = sequenceBits + workerIdBits;
// 时间毫秒左移22位
private final static long timestampLeftShift = sequenceBits + workerIdBits + datacenterIdBits;
private final static long sequenceMask = -1L ^ (-1L << sequenceBits);
/* 上次生产id时间戳 */
private static long lastTimestamp = -1L;
// 0,并发控制
private long sequence = 0L;
private final long workerId;
// 数据标识id部分
private final long datacenterId;
public IdWorker(){
this.datacenterId = getDatacenterId(maxDatacenterId);
this.workerId = getMaxWorkerId(datacenterId, maxWorkerId);
}
/**
* @param workerId
* 工作机器ID
* @param datacenterId
* 序列号
*/
public IdWorker(long workerId, long datacenterId) {
if (workerId > maxWorkerId || workerId < 0) {
throw new IllegalArgumentException(String.format("worker Id can't be greater than %d or less than 0", maxWorkerId));
}
if (datacenterId > maxDatacenterId || datacenterId < 0) {
throw new IllegalArgumentException(String.format("datacenter Id can't be greater than %d or less than 0", maxDatacenterId));
}
this.workerId = workerId;
this.datacenterId = datacenterId;
}
/**
* 获取下一个ID
*
* @return
*/
public synchronized long nextId() {
long timestamp = timeGen();
if (timestamp < lastTimestamp) {
throw new RuntimeException(String.format("Clock moved backwards. Refusing to generate id for %d milliseconds", lastTimestamp - timestamp));
}
if (lastTimestamp == timestamp) {
// 当前毫秒内,则+1
sequence = (sequence + 1) & sequenceMask;
if (sequence == 0) {
// 当前毫秒内计数满了,则等待下一秒
timestamp = tilNextMillis(lastTimestamp);
}
} else {
sequence = 0L;
}
lastTimestamp = timestamp;
// ID偏移组合生成最终的ID,并返回ID
long nextId = ((timestamp - twepoch) << timestampLeftShift)
| (datacenterId << datacenterIdShift)
| (workerId << workerIdShift) | sequence;
return nextId;
}
private long tilNextMillis(final long lastTimestamp) {
long timestamp = this.timeGen();
while (timestamp <= lastTimestamp) {
timestamp = this.timeGen();
}
return timestamp;
}
private long timeGen() {
return System.currentTimeMillis();
}
/**
* <p>
* 获取 maxWorkerId
* </p>
*/
protected static long getMaxWorkerId(long datacenterId, long maxWorkerId) {
StringBuffer mpid = new StringBuffer();
mpid.append(datacenterId);
String name = ManagementFactory.getRuntimeMXBean().getName();
if (!name.isEmpty()) {
/*
* GET jvmPid
*/
mpid.append(name.split("@")[0]);
}
/*
* MAC + PID 的 hashcode 获取16个低位
*/
return (mpid.toString().hashCode() & 0xffff) % (maxWorkerId + 1);
}
/**
* <p>
* 数据标识id部分
* </p>
*/
protected static long getDatacenterId(long maxDatacenterId) {
long id = 0L;
try {
InetAddress ip = InetAddress.getLocalHost();
NetworkInterface network = NetworkInterface.getByInetAddress(ip);
if (network == null) {
id = 1L;
} else {
byte[] mac = network.getHardwareAddress();
id = ((0x000000FF & (long) mac[mac.length - 1])
| (0x0000FF00 & (((long) mac[mac.length - 2]) << 8))) >> 6;
id = id % (maxDatacenterId + 1);
}
} catch (Exception e) {
System.out.println(" getDatacenterId: " + e.getMessage());
}
return id;
}
}
至此,公共模块common搭建完毕。
三、小结
通过该篇文章,主要学会了:
- 搭建父工程
- 搭建公共模块,创建通用返回类
- 分布式ID生成器(snowflake算法)